By the expression "hydrophilic image-precursor layer" as used herein a hydrophilic layer is meant that can be a photosensitive silver halide hydrophilic layer or a hydrophilic layer in which an image can be formed e.g. by receiving an image from a donor element such as by the silver salt diffusion transfer reversal method (DTR-method).
In several photographic fields e.g. microphotography, astrophotography, aerophotography, photogrammetry, holography, recording of nucleophysical phenomena, the preparation of masks for use in the production of microelectronic integrated circuits or printed circuit boards (PCB), the preparation of lithographic offset printing forms e.g. according to the DTR-method, the dimensional stability of the photographic material used for making the desired record is of utmost importance, and this applies to such photographic material both in unprocessed and processed state.
Photographic materials comprise at least one hydrophilic layer coated on a support. Polymer film supports such as cellulose acetate and polyester supports have the disadvantage of absorbing water both in vapour and in liquid form. Owing to the absorption of water vapour from the atmosphere or of fluid water from processing liquids e.g. developing baths the dimensions of polymer film supports start changing. The hydrophilic layer(s) tightly adhering to the polymer film supports have to follow these dimensional changes and undergo internal stresses. As a consequence, the dimensions of the recorded image data may differ inacceptably from those of the recorded subject.
In the past, glass plates have been used customarily when photographic supports having a high dimensional stability were needed, especially in the photographic fields specified above. Glass does not absorb water vapour or fluid water and has, therefore, found extensive use as a transparent dimensionally stable support in these photographic fields. Nevertheless, glass has the disadvantage of being heavy, voluminous, and fragile. Moreover, the coating of photographic hydrophilic layers on glass plates and the sizing of the coated material poses great problems, especially when continuous coating and sizing are desired.
Attempts have therefore been made in recent years to enhance the dimensional stability of polyester film supports for photographic use by inhibiting or at least retarding absorption of water vapour or fluid water by these supports.
It is known for instance from U.S. Pat. No. 4,933,267 to coat a polyester film support for a silver halide photographic material, at least one side of said support having a polymer latex, on both sides with a polymer layer comprising a copolymer containing fom 50 to 99.5% by weight of vinylidene chloride, both polymer layers having a thickness of at least 0.3 .mu.m.
In EP-A 343,642 a silver halide photographic material has been described, which is composed of a polyester film support having thereon at least one hydrophilic colloid layer containing a polymer latex and between the support and the hydrophilic colloid layer a layer containing a vinylidene chloride copolymer core-shell latex, at least one hydrophilic colloid layer being a light-sensitive silver halide emulsion layer.
However, polyester film supports coated with vinylidene chloride copolymer layers have the disadvantage of providing insufficient tightness to water and water vapour. Moreover, the use of chlorine-containing compounds such as vinylidene chloride copolymers raises ever growing environmental objections since combustion of waste material comprising such chlorine-containing copolymers may lead to the production of toxic chlorine gas, which itself in the presence of organic compounds may form other toxic substances such as dioxine.
In U.S. Pat. No. 3,864,132 a photographic material has been described, which is composed of a hydrophobic polymer supporting surface, a subbing layer, and a hydrophilic colloid layer, wherein said subbing layer essentially consists of an inorganic oxide sush as silicon monoxide or silicon dioxide.
Unfortunately, a silicon monoxide or silicon dioxide layer is far too permeable to water liquid or vapour and thus has no satisfactory barrier function.
In GB-A 2,074,345 a pre-holographic element has been described, which is composed of an optically transparent hydrophobic support, a layer of a glassy, optically transparent, polar, moisture barrier material formed at a temperature that should not deform said support, and a hydrophilic photosensitive material. The glassy layer is a silicon dioxide layer deposited by electron beam and having a high thickness of 0.2 to 10 .mu.m.
Such thick glassy layers may lead to inhomogeneity of the glassy material; cracks may indeed appear. Furthermore, the transparency of thicker layers is reduced. These disadvantages are frequently encountered in the case of special processing conditions such as high temperature development.